IV] 



CHLOROPHYLL 



35 



Expt. 30. The action of chlorophyllase. Fresh leaves of a species rich in chloro- 

 phyllase, e.g. Heracleum or Galeopsis^ are finely divided and put in a 70 % acetone 

 solution, 3 c.c. of solution being used for every gram of leaf. The chlorophyll, by 

 means of the chlorophyllase, is hydrolyzed into phytol and the acid chlorophyllide. 

 This can be demonstrated after about a quarter of an hour if the solution is diluted 

 with water, transferred to ether and shaken with 0'05 % sodium hydroxide. The 

 sodium hydroxide takes up more colouring matter the further the enzyme action 

 has progressed. 



Expt 31. The destruction of chlorophyllase. If fresh leaves of a species rich in 

 chlorophyllase are first steeped in boiling water for a few minutes before they are 

 placed in the acetone solution, unaltered chlorophyll is extracted which does not 

 react with dilute alkali. 



With acids — >■ 



(C32H3oON4Mg) (COOCH3) (COOC20H39) J. (C32H32ON4) (COOCH3) (COOC20H39) 



chlorophyll a 



phaeophytin 



(C32H3oON4Mg) (COOH) (COOH) 



chlorophyllin a 

 and isochlorophyllin a 



interme 



diate phyllins 



C3iH34N4Mg 



aetiophyllin 



;C32H320N4) (COOH) (COOH) 



phytochlorin e 



and phytochlorins/and g 



intermediate porphyrins 



Scheme 1. 



— ^ C31H36N4 

 aetioporphyrin 



chlorophyll a 

 <MgN4C32H3oO)(COOCH3)(COOC2oH39) 



with 



meythl chlorophyllide a 



<MgN4C32H3oO) (COOCH3) (COOCH3) 



chlorophyllide a 

 (MgN4C32H3oO) (COOCH3) (COOH) 



dilute acid 



with 



dilute acid 



phaeophytin a 

 (N4C32H32O) (COOCH3) (COOC2 



with 



dilute acid 

 Scheme 2. 



1H39) 



03 



methyl phaeophorbide a 

 (N4C32H32O) (COOCH3) (COOCH3) 



§ 



phaeophorbide a 

 (N4C32H32O) (COOCH3) (COOH) 



By treatment with acids, magnesium is removed from the chlorophyl- 

 lides, with the production of the corresponding phaeophorbides. Thus 

 methyl chlorophyllide a gives methyl phaeophorbide a, etc. (see Scheme 2, 

 above). 



3—2 



